There are known methods for manufacturing semiconductor light emitting devices including an electrode formation step of forming an n-side electrode having a metallic layer composed of Ni on a semiconductor layer.
For example, Patent Literature 1 discloses a method for manufacturing a semiconductor light emitting device including an n-type semiconductor layer, a p-type semiconductor layer, a p-side electrode, and an n-side electrode sequentially laminated on a substrate.
The n-type semiconductor layer is formed on the substrate. On the n-type semiconductor layer, the p-type semiconductor layer is formed. The p-type semiconductor layer is partially removed by etching so that a part of the n-type semiconductor layer is exposed. A part of the p-side electrode is provided for a part of the p-type semiconductor layer remaining without being removed, and the n-side electrode is provided for a part an area where the n-type semiconductor layer is exposed. Each of the p-side and n-side electrodes is composed of a laminating layered structure of Ni, Ti, and Au.
In the method for manufacturing a light emitting device, the n-type and p-type semiconductor layers are laminated on the substrate, and then a part of the p-type semiconductor layer is removed by etching to expose a part of the n-type semiconductor layer. Next, a patterned resist film is formed on a predetermined region of the p-type and n-type semiconductor layers. Subsequently, Ni, Ti, and Au are sequentially layered by vacuum deposition to form a metallic layer. Part of the metallic layer on the resist film is removed by the lift-off process to form the p-side and n-side electrodes.
Herein, in the semiconductor light emitting device of Patent Literature 1, in order to reduce the contact resistance between the p-side and n-side electrodes and respective p-type and n-type semiconductor layers, the Ni and Ti metallic layers are formed in a thin thickness such that the adhesion between the both electrodes and both semiconductor layers in an not-degraded level are attained. It is therefore possible to reduce operating voltage of the semiconductor light emitting device to some extent.
Patent Literature 1 Japanese Patent Laid-open Publication No. 9-232632